Add support to *not* monitor temperature of a list of drives.

[JeffCurless]

The problem I am specifically trying to solve is that my cooling fan almost always runs pretty much flat out. I have an external disk which runs hotter than I’d like (although totally stock and how WD intended it). I think the hot external USB drive is reporting that it is hot and the fan is spinning up to try to cool it but of course having no effect. My theory is that if I can either exclude the usb external disk from the monitoring, or somehow set its temperature to report colder than it is, I can avoid the unnecessary fan noise, whilst leaving a sensible cooling profile for the 2 internal disks.